Method of forming cylinder ends



Def. *1, 1946. J; J. BEDNAR EI'AL ,40 6

METHOD'OF FORMING CYLINDER ENDS Filed March 13, 1944 '2 Sheets-Sheet lOct. 1, 1946. J. J. BEDNAR EI'AL 2,408,596 METHOD OF FORMING CYLINDERENDS- Filed March 13, 1944 2 Sheets-Sheet? 721545 Mal mi.

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Patented Oct. 1, 1946 2,408,596 I METHOD OF FORMING CYLINDER ENDS JosephJ. Bedna and Steven P. Peck, McKeesport, 2a., assig'nors, to NationalTube Company, a corpora ion of. New J ersey Application March 13, 1944,Serial No. 526,253

2, Claims, (Cl. 29-1482) This invention relates to an improved method ofspinning integral ends oncylindersto adapt them for high-pressureservice.

Heretofore the spinning of cylinder ends has been quite definitelyrestricted touse on small cylinders suited only for low-pressure work.One object of the present invention is to provide a method for buildingup the thickness of an end section of a tube or cylinder which willadapt it for high-pressure service.

A further object isv to provide a method involving the building up ofthe end thickness of a cylinder by spinning and subsequently eliminating the fissure or feathers formed in the region of the original pointof juncture of the end edges.

As will appear more fully hereinafter, our improved method involvesspinning integral closed ends on tubular metal workpieces to form aclosure capable of withstanding a pressure of 2500 pounds per squareinch or greater, the method.

being characterized by rotating the workpiece while. applying awork-engaging tool to the end portion thereof, moving said tool througharcs 2 dition of the tube orcylinder and the difierent stages in theoperation of the method.

Figure 7 illustrates a step in the method wherein the mid-portion of thebuilt-up metal of increasedthickness is forced inwardly into engagementwith a die member.

Figure 8 illustrates the step of removing feather-like portionsresulting from the operation of Figure 7.

Figure 9 is a detail portion of an end of a cylinder made in accordancewith the herein claimed method.

Referring in detail to the drawings, l0 represents a conventional formof chuck adapted to grip a tubular or cylindrical workpiece l2. Thischuck is rotatably supported by a suitable spindle M of conventionalform Which is rotated by any suitable means such as a belt l6 connectedto a power drive (not shown). The chuck and its driving means areadapted to rotate the tubular workpiece I2 at a speed of approximately1400 R. P. M. Mounted in juxtaposition with the extending from theperiphery toward the longi- Y tudinal axis'of the workpiece, also movingthe tool axially of the workpiece, to bring the end edges of saidworkpieceforcibly into abutment. in the region of the longitudinal'axisthereof,

' cry to a point beyond the longitudinal axis of the workpiece, so as toupset said end portion and thereafter continuing the movement of saidtocl in arcuate paths extending from the periphand build up metal ofincreased thickness without a fissure outside the original point ofjuncture of said edges, then stopping the rotating and thereafterpressing the mid-portion of the closed end inwardly into engagement witha die memher having an axial recess opposite the point of juncture ofsaid edges, whereby feather-like portions in the axial region adjacentsaid point of juncture are pressed into said recess, and thereafterremoving said feather-like portions.

For a full understanding of the invention, reference should be made tothe following detailed disclosure, the accompanying drawings, and theappended claims.

In the drawings:

Figure 1 is a plan view of conventional apparatus suitable for carryingout the present invention.

an initial step of the imchuck I 0 is a tool bed [8 having slidablymounted thereon a table 20 which canbe reciprocated back and forth byany suitable means in the direction lengthwise of the work.

A compound tool rest. 22 is pivoted at 24 at 1 a, point'ecccntri tothelongitudinal axis of the workpiece I2. The tool rest carries a slide 26which supports a tool holder 2,8 carrying a tool 30 which is preferably,although not necessarily, in the form of a roller pivotally mounted in abearing 32, so that the tool can make a, rolling contact with the endportion of the tubular workpiece l2. Prior to the operations about to bedescribed, the end portion of the workpi ce will usually be locallyheated, for example, by the impingement of flames from oxyacetylenetorches such as indicated at 34 and 36. The torches are eifective tomaintain the end of the workpiece at the optimum spinning temperature ofapproximately 2000 to 2200 F. The torch 36 is mounted adjacent thecompound rest 22, and the torch 34 is mounted on any stationary portionof the apparatus.

In starting the improved method, after the work is properly heated, thetool 30 is moved to the position of Figure 2, where the leading edge ofthe periphery of the tubular workpiece is engaged. After such engagementthe tool rest 22 is swung about its pivot 24; for example, from theposition of Figure 2 to the position of Figure i3, through the arcuatepath indicated by the dotted arc a:.y, the tool'at this time swingingabout a radius r struck from the center 24 which,

as shown, is in plan and is offset from the longitudinal central axis ofthe workpiece [2.

The tool 30 is moved back and forth along its arcuate path severaltimes, with the result that metal from the outer normally cylindricalportion is flowed inwardly, thus thickening the end region of thetubefrom the normal gauge of the workpiecetothe thickened conditionsuggested in Figure 3. Subsequent arcuate sweeps or the tool 3!] with anaccompanying endwise movement of the tool toward the work graduallyspins in the end of the tube'until it is substantially closed, as shownin r stroke of the tool 38 is then increased to the position such assuggested in Figure 5, thus completely closing the tube end and bringingthe Figure 4. Ihe arcuate end edges initially into abutment in theirri'mediate region of the longitudinal axis of the workpiece l2. Atthis stage of the methodfithere will be present a fissure f in the zoneof initial abutment of the end edges of the tube. Thereafter the tool 30is given a plurality of additional arcuate sweeps to the positionindicated in Figure 6, where the working face of the tool crosses thelongitudinal axis of the end of' the workpiece. This is for the purposeof building up worked metal of substantial thickness without'a-fis'sure, beyond the original point of juncture of the end edges.This condition is illustrated in Figure 6, wherein it is noted that thefissure ends at the'point j, and the metal beyond that point is entirelydevoid of a'fissure and is thus rendered more dense so that it isthereby made capable ofwithstanding' considerable pressure.

Upon completion of the operation represented in Figure 6, the workpieceis removed from the chuck l and the end thereof is entered into thecavity 38 of a die 4!). Thereupon another die 42 having a central recess44 therein is forced inwardly, withthe result that featherlike portions46 located in the longitudinal central axial region "of'the' workpieceand flanking the central fissure, are forced inwardly into, the recess44 of the die 42'. moved and the work-piece is disengaged from the die'42. The workpiece is then chucked in a suitable metal working toolsuch'as a lathe or the like, and a cutter bar 48 centered byaguide restand carrying a spade or similar cutting tool 52 is brought into play, soas to machine Ifhedie 42 is then re solid section free from physical offthe projecting feather-like portions which flank the fissure. At theconclusion of this operation the interior of the cylinder will have thefinished face 54 and the exterior will have a dished cavity 56, as shownin Figure 9.

It will be understood that in the machine operation of Figure 8, thefeathers 46 flankin the fissure .willbe eliminated. .Thus the endclosure or bottom of the cylinder is a dense homogeneous defects andsumcient to withstand high commercial test pressures of the order of2500 to 3500 pounds per square inch.

While we have shown and described precise operating steps, it is to beunderstood that the drawings and descriptive matter are to beinterpreted in an illustrative rather than a limiting sense, sincevarious modifications may be made within the scope of the appendedclaims.

We claim: 7

l, A method of spinning closed ends on tubular metal workpieces,comprising rotating the workpiece and applying a work-engaging tool tothe end portion thereof, moving said tool through arcs extending fromthe periphery toward'the longitudinal axis of the workpiece, moving saidtool longitudinally of the axis of the workpiece to bring the end edgesof said workpiece into abutment in the region of the longitudinal axisthereof, and thereafter continuing the movement of said tool in-arcsextending from the periphery tothe point beyond'the longitudinal axis ofthe workpiece to upset said end portion and build upmetal of substantialthickness without a fissure outside the original point or juncture ofsaid edges, stopping rotation of the workpiece, then extrudingthe axialportion of said closed end inwardly'into an axial cavityin a die memherin the'region of the point of juncture of said edges," said extrudingstep causing featherlike portions to be forced axially into said diecavity, and finally removing said axially extruded feather-likeportions; I i

' 2; The method of claim 1, further characterized-- by the step offacilitating the upsetting operation bydirecting heat locally againstthe end. portion of the workpiece while actuating said tool to upset theend portion of the work.

JOSEPH J. -BEDNAR. STEVEN P. PECK.

